A fluid heater for a heating fluid and having a fluid inlet and a fluid outlet may comprise a heater housing defining an interior with a combustion chamber being positioned in the interior of the housing, and fluid tubing in the interior of the housing and adjacent to the combustion chamber, with the fluid tubing defining a fluid path through the housing between the fluid inlet and the fluid outlet. The heater may also include a burner configured to combust a fuel in the combustion chamber to heat the fluid tubing. At least a portion of the fluid path may comprise a bifurcated fluid path between the fluid inlet and the fluid outlet.